Variable geometry turbocharger

ABSTRACT

A variable geometry turbocharger is provided. The turbocharger improves efficiency by controlling flow to the rotor ( 230 ) via movable vanes ( 260 ). The vanes ( 260 ) can be rotated using a pin ( 380, 480 ) and groove ( 385, 485 ) system. The vanes ( 260 ) can be multiple structures ( 710, 730 ) that are movable with respect to each other to increase the length of each of the vanes ( 260 ). The turbocharger also improves efficiency by creating a better seal in the area between the vanes ( 260 ) and the adjustment ring ( 240 ). The seal can be provided by biasing the adjustment ring ( 240 ) towards each of the vanes ( 260 ). The seal can be provided by expanding each of the vanes ( 260 ). The seal can be provided by having a movable portion ( 1150 ) of the adjustment ring ( 240 ) that is actuated by a pressure source or the like and axially moves towards the vanes ( 260 ). The plurality of vanes ( 260 ) can be low solidity vanes.

FIELD OF THE INVENTION

The invention relates in general to turbochargers and, moreparticularly, to variable geometry turbochargers.

BACKGROUND OF THE INVENTION

Turbochargers are widely used on internal combustion engines and, in thepast, have been particularly used with large diesel engines, especiallyfor highway trucks and marine applications.

More recently, in addition to use in connection with large dieselengines, turbochargers have become popular for use in connection withsmaller, passenger car power plants. The use of a turbocharger inpassenger car applications permits selection of a power plant thatdevelops the same amount of horsepower from a smaller, lower massengine. Using a lower mass engine has the desired effect of decreasingthe overall weight of the car, increasing sporty performance, andenhancing fuel economy and reducing the aerodynamic drag of the vehicle.Moreover, use of a turbocharger permits more complete combustion of thefuel delivered to the engine, thereby reducing the overall emissions ofthe engine, which contributes to the highly desirable goal of a cleanerenvironment.

The design and function of turbochargers are described in detail in theprior art, for example, U.S. Pat. Nos. 4,705,463, 5,399,064, and6,164,931, the disclosures of which are incorporated herein byreference.

Turbocharger units typically include a turbine operatively connected tothe engine exhaust manifold, a compressor operatively connected to theengine air intake system, and a shaft connecting the turbine andcompressor so that rotation of the turbine wheel causes rotation of thecompressor impeller. The turbine is driven to rotate by the exhaust gasflowing from the exhaust manifold. The compressor impeller is driven torotate by the turbine, and, as it rotates, it increases the air massflow rate, airflow density, air pressure and temperature delivered tothe engine cylinders.

As the use of turbochargers finds greater acceptance in passenger carapplications, three design criteria have moved to the forefront. First,the market demands that all components of the power plant of either apassenger car or truck, including the turbocharger, must providereliable operation for a much longer period than was demanded in thepast. That is, while it may have been acceptable in the past to requirea major engine overhaul after 80,000-100,000 miles for passenger cars,it is now necessary to design engine components for reliable operationin excess of 150,000 miles of operation. It has been necessary to designengine components in trucks for reliable operation in excess of1,000,000 miles of operation for some time. This means that extra caremust be taken to ensure proper design and fabrication and cooperation ofall supporting devices.

The second design criterion that has moved to the forefront is that thepower plant must meet or exceed very strict requirements in the area ofminimized NO_(x) and particulate matter emissions. Third, with the massproduction of turbochargers, it is highly desirable to design aturbocharger that meets the above criteria and is comprised of a minimumnumber of parts. Further, those parts should be easy to manufacture andeasy to assemble, in order to provide a cost effective and reliableturbocharger.

Turbocharger efficiency over a broad range of operating conditions isenhanced if the flow of motive gas to the turbine wheel can bemodulated. One method for achieving this level of control is to make thevanes pivotable so as to alter the geometry of the passagestherebetween. The design of the mechanism used to effect pivoting of thevanes is critical to prevent binding of the vanes. Other considerationsinclude the cost of manufacture of parts and the labor involved inassembly of such systems.

Additionally, the design of the vane is critical to both the efficiencyof the gas delivery to the turbine, as well as the reliability of thevariable geometry assembly. While movement of the vanes allows forcontrol of the gas delivery, it also adds the problem of leakage pastthe moveable vanes. Additionally, due to the extreme environment thatthe moveable vanes are placed in, the structure of the vanes, especiallywhere pivotally connected via vane posts and the like, must be sound toavoid failure.

In U.S. Published Application 20050207885 to Daudel, the Applicantsattempt to control fluid delivery to the compressor wheel by providingmovable guide vanes. As shown in FIG. 1, a variable diffuser geometry 13on a rear compressor wall 14 comprises a plurality of annularly arrangedguide vanes 16 which are uniformly distributed over the circumferenceand each of which includes a guide vane shaft 17. The guide vane shaft17 of each guide vane 16 is pivotally supported in a support ring 18which is surrounded by an adjustment ring 19. The radially inner end ofthe adjustment ring 19 is rotatably supported on the radially outercircumference of the support ring 18. The adjustment ring 19 includes aplurality of adjustment elements 20 in the form of pins arranged at anaxial front side of the adjustment ring 19. The adjustment ring 19 isengaged by an adjustment member 21 in the form of an operating rod forrotating the adjustment ring 19.

The Daudel adjustment member 21 is operated by an actuator 21′. Theadjustment member 21 is capable of rotating the adjustment ring 19, sothat the adjustment elements 20 are moved circumferentially by a certainangle whereby the guide vanes 16 on the support ring 18 are pivoted by acorresponding angle about their guide vane shaft 17. Each guide vane 16is fork-like shaped with two spaced fork tines 22 and 23 disposed attheir outer ends between which a radially outwardly open engagementchannel is formed into which the adjustment element 20 extends in anyposition of the adjustment ring 19. During an adjustment movement of theadjustment ring 19 in the direction of the arrow 25, the guide vanes 16can be guided in any position of the adjustment ring 19.

The Daudel system suffers from the drawback of requiring a complicatedsystem with numerous parts. The Daudel system further suffers from thedrawback of only allowing for a particular range of motion for controlof the fluid flow.

In U.S. Pat. No. 6,679,057 to Arnold, the Applicant attempts to controlflow to the volute by providing movable guide vanes. As shown in FIG. 2,the Arnold system has a turbocharger 110 with a turbine housing 112adapted to receive exhaust gas from an internal combustion engine anddistribute the exhaust gas to an exhaust gas turbine wheel or turbine114 rotatably disposed within the turbine housing 112 and coupled to oneend of a common shaft 116. The turbine housing 112 encloses a variablegeometry member 117 that comprises a plurality of pivotably moving vanes118 disposed therein. A turbine adjustment or unison ring 119 ispositioned within the turbine housing 112 adjacent the vanes 118 toengage the vanes and effect radially inward and outward movement of thevanes vis-a-vis the turbine in unison. The turbine unison ring 119comprises a plurality of slots 120 disposed therein that are configuredto provide a minimum backlash and a large area contact when combinedwith correspondingly shaped tabs 122 that project from each of theturbine vanes 118. The turbine unison ring 119 is rotatably positionedwithin the housing, and is configured to engage and rotate turbine vanesthrough identical angular movement.

The turbine unison ring 119 comprises an elliptical slot 123 that isconfigured to accommodate placement of an actuator pin 124 therein forpurposes of moving the unison ring within the housing. The pin 124 isattached to one end of an actuator lever arm 126, that is attached atits other opposite end an actuator crank 128. The turbine actuating pin124 and lever arm 126 are each disposed within a portion of theturbocharger center housing 130 adjacent the turbine housing. Theactuator crank 128 is rotatably disposed axially through theturbocharger center housing 130, and is configured to move the lever arm126 back and forth about an actuator crank longitudinal axis, whichmovement operates to rotate the actuating pin 124 and effect rotation ofthe unison ring 119 within the turbine housing. Rotation of the unisonring 119 in turn causes the plurality of turbine vanes to be rotatedradially inwardly or outwardly vis-a-vis the turbine 114 in unison.

The turbocharger 110 also comprises a compressor housing 131 that isadapted to receive air from an air intake 132 and distribute the air toa compressor impeller 134 rotatably disposed within the compressorhousing 131 and coupled to an opposite end of the common shaft 116. Thecompressor housing also encloses a variable geometry member 136interposed between the compressor impeller and an air outlet. Thevariable geometry member is in the form of radial diffuser and comprisesa plurality of pivoting vanes 138. A compressor adjustment or unisonring 140 is rotatably disposed within the compressor housing 131 and isconfigured to engage and rotatably move all of the compressor vanes 138in unison. The compressor unison ring 140 comprises a plurality of slots142 disposed therein that are each configured to provide a minimumbacklash and a large area contact when combined with correspondinglyshaped tabs 144 projecting from each respective compressor vane. Thecompressor unison ring 140 effects rotation of the plurality ofcompressor vanes 138 through identical angular movement.

The compressor adjustment ring 140 comprises a slot and an actuating pin146 that is rotatably disposed within the slot. An actuating lever arm148 is attached at one of its end to the actuating pin 146, and isattached at another one of its ends to an end of the actuator crank 128opposite the turbine unison ring lever arm 126. The compressor unisonring actuating pin 146 and lever arm 148 are disposed through a backingplate 150 that is interposed between the turbocharger compressor housing131 and the center housing 130. The actuator crank 128 is rotatablydisposed through the center housing 130. Rotation of the actuator crank128 causes the compressor unison actuating lever arm 148 to move arounda longitudinal axis of the actuator crank, which in turn effectsrotation of the compressor unison ring actuating pin 146. Rotation ofthe actuating pin 146 causes the compressor unison ring 140 to rotatealong the backing plate 150, which in turn causes each of the compressorvanes 138 to be pivoted radially inwardly or outwardly vis-a-vis thecompressor impeller 134.

The Arnold system suffers from the drawback of requiring a complicatedsystem with numerous parts. The Arnold system further suffers from thedrawback of only allowing for a particular range of motion for controlof the fluid flow.

Thus, there is a need for a variable geometry system that effectivelyand efficiently controls fluid flow from the compressor wheel. There isa further need for such a system that is reliable and cost-effective.There is yet a further need for such a system that facilitates assemblyof the turbocharger.

SUMMARY OF THE INVENTION

The present disclosure provides an efficient and cost-effective systemfor controlling fluid from the compressor impeller of a turbocharger.The system facilitates assembly of the turbocharger by reducing therequirement for precision fit. The system further improves efficiency bycreating a better seal between the vanes and the mating surfaces againstwhich they control the airflow.

In one aspect of the invention, a turbocharger is provided comprising acompressor housing; a compressor rotor rotatably mounted in thecompressor housing; a supply channel for supplying a compressible fluidfrom the compressor rotor; and a vane ring assembly having an adjustmentring and a plurality of vanes. The plurality of vanes are distributed inan annular vane space and are movable to control flow of thecompressible fluid. The vane angle of attack can be changed using avariety of methods. The plurality of vanes (260) can be low solidityvanes.

In another aspect, a turbocharger is provided comprising: a housing; arotor rotatably mounted in the housing; a supply channel for supplying afluid to the rotor; and a vane ring assembly having first and secondnozzle rings. The first nozzle ring is fixed with respect to theturbocharger and has a plurality of first vanes. The second nozzle ringis rotatable with respect to the turbocharger and has a plurality ofsecond vanes. Each of the plurality of first and second vanes isdistributed in an annular vane space. Each of the plurality of first andsecond vanes is non-rotatable with respect to the first and secondnozzle rings. The second nozzle ring is rotatable from a first positionto a second position. In the first position, the plurality of firstvanes are aligned with the plurality of second vanes. In the secondposition, the plurality of first vanes are non-aligned with theplurality of second vanes.

In another aspect, a turbocharger is provided comprising: a housing; arotor rotatably mounted in the housing; a supply channel for supplying afluid to the rotor; and a vane ring assembly having an adjustment ringand a plurality of vanes. The plurality of vanes are distributed in anannular vane space and are movable to control flow of the fluid. Each ofthe plurality of vanes is connected to the turbocharger by a rotatablepin. The adjustment ring has a sealing portion that is axially movabletowards the plurality of vanes. The sealing portion is in communicationwith an actuator. The actuator causes the sealing portion to movetowards the plurality of vanes to reduce a gap therebetween.

The turbocharger may further comprise a biasing mechanism that biasesthe adjustment ring towards the plurality of vanes. The biasingmechanism can be a spring. The biasing mechanism may be a plurality ofsprings. The turbocharger can further comprise a biasing mechanism thatbiases each of the plurality of vanes towards the adjustment ring. Eachof the plurality of vanes can be first and second portions that aremoveable with respect to each other, and the biasing mechanism canexpand each of the plurality of vanes.

The biasing mechanism may be at least one spring positioned between thefirst and second portions. The biasing mechanism can be a compressiblematerial. The turbocharger can further comprise a biasing mechanism thatbiases the first and second nozzle rings towards the plurality of firstand second vanes. The actuator can be a pressure source in communicationwith the sealing portion via a channel. The pressure source may bepneumatic or hydraulic.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a variable geometry compressor of aturbocharger according to U.S. Published Patent Application No.20050207885;

FIG. 2 is a cross-sectional view of another variable geometry compressorof a turbocharger according to U.S. Pat. No. 6,679,057;

FIG. 3 is a cross-sectional view of a portion of a variable geometrycompressor according to an exemplary embodiment of the invention;

FIG. 4 a is a cross-sectional view of a portion of a variable geometrycompressor according to another exemplary embodiment of the invention;

FIG. 4 b is a plan view of a vane used with the variable geometrycompressor of FIG. 4 a;

FIG. 5 a is a cross-sectional view of a portion of a variable geometrycompressor according to another exemplary embodiment of the invention;

FIG. 5 b is a plan view of a vane used with the variable geometrycompressor of FIG. 5 a;

FIG. 6 a is a cross-sectional view of a portion of a variable geometrycompressor according to another exemplary embodiment of the invention;

FIG. 6 b is a plan view of a vane used with the variable geometrycompressor of FIG. 6 a;

FIG. 7 is a cross-sectional view of a portion of a variable geometrycompressor according to another exemplary embodiment of the invention;

FIG. 8 is a plan view of a portion of a variable geometry compressoraccording to another exemplary embodiment of the invention;

FIG. 9 is a plan view of a portion a variable geometry compressoraccording to another exemplary embodiment of the invention;

FIG. 10 is a plan view of a portion of the variable geometry compressorof FIG. 9 in a second position;

FIG. 11 a is a cross-sectional view of a portion of a variable geometrycompressor according to another exemplary embodiment of the invention;

FIG. 11 b is a cross-sectional view of the variable geometry compressorof FIG. 11 a in a biased state;

FIG. 12 a is a perspective view of a vane of a variable geometrycompressor according to another exemplary embodiment of the invention;

FIG. 12 b is a perspective view of the vane of FIG. 12 a in an un-biasedstate;

FIG. 13 is a cross-sectional view of a portion of a variable geometrycompressor according to another exemplary embodiment of the invention;and

FIG. 14 is a schematic representation a variable geometry compressoraccording to another exemplary embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Exemplary embodiments described herein are directed to a variablegeometry compressor system for a turbocharger. Aspects will be explainedin connection with several possible embodiments of the system, but thedetailed description is intended only as exemplary. The particular typeof turbocharger that utilizes the exemplary embodiments of the vane andvane assemblies described herein can vary. The several embodiments aredescribed with respect to vanes for the compressor wheel. Exemplaryembodiments are shown in FIGS. 3-14, but the present disclosure is notlimited to the illustrated structure or application. In one embodiment,the moveable guide vanes are low solidity vanes (i.e., low ratio of gapto chord). For example, the low solidity can be less than one.

A portion of a turbocharger system as shown in FIG. 3 includesturbomachinery in the form of a compressor housing 210, a bearinghousing 220, a compressor wheel 230, an adjustment ring 240 and a flowchannel 250. The flow channel or vane space 250 has a series of guidevanes 260 that allow for control of flow therethrough and thusadjustment of flow to the compressor wheel 230. The adjustment force forthe vane 260 is applied at region 270, while the pivot point is along apin or other rotation mechanism 265. The particular size or shape ofeach of the vanes 260 can be chosen based upon a number of factorsincluding flow efficiency. The embodiment of FIG. 3 uses a singlebearing, which is pin 265. However, the present disclosure contemplatesthe use of bearings on both sides of the vanes 260.

FIGS. 4 a and 4 b show a variable geometry compressor system having thecompressor housing 210, the adjustment ring 240 and the flow channel250. The adjustment force for the vane 360 is applied at region 270,while the pivot point is along the pin or other rotation mechanism 265.An adjustment pin 380 is connected to the adjustment ring 240 and ishoused in a groove 385 of the vane 360. Annular movement of theadjustment ring 240 and thus adjustment pin 380 causes selective slidingof the pin within groove 385 and rotation of the vane 360.

FIGS. 5 a and 5 b show a variable geometry compressor system having thecompressor housing 210, the adjustment ring 240 and the flow channel250. The adjustment force for the vane 460 is applied at region 270,while the pivot point is along the pin or other rotation mechanism 265.An adjustment pin 480 is connected to the vane 460 and is housed in agroove 485 of the adjustment ring 240. Annular movement of theadjustment ring 240 and thus groove 485 causes selective sliding of thepin within groove 485 and rotation of the vane 460.

FIGS. 6 a and 6 b show a variable geometry compressor system having thecompressor housing 210, the adjustment ring 240 and the flow channel250. The adjustment force for the vane 560 is applied at region 270,while the pivot point is along the pin or other rotation mechanism 265.A pair of opposing adjustment pins or a fork 580 abuts the vane 560 andis connected to the adjustment ring 240. Annular movement of theadjustment ring 240 and thus fork 580 causes rotation of the vane 560about the axis defined by pin 265.

Rotation of the adjustment ring 240 for the above-described embodimentscan be by various structures and techniques including gear pairing,lever mechanisms and/or chain drives. Various sizes and shapes can beused for the components described above including the grooves, pins andforks based upon various factors including flow efficiency and effectingselected motion of the vanes 560.

FIG. 7 shows a variable geometry compressor system having the compressorhousing 210, the adjustment ring 240 and the flow channel 250. Theadjustment force for the vane 660 is applied along the pin or otherrotation mechanism 665. For example, an adjustment moment can be appliedto pin 665 via a gear 670 operably connected to an actuation device 680.Rotation of the adjustment ring 240 causes rotation of the gear 670 dueto its connection to the actuation device 680.

FIG. 8 shows a variable geometry compressor system that allows forchange of angle of attack or profile of the vane set. The system has afirst fixed nozzle ring 700 having a series of fixed guide vanes 710attached thereto and a second rotatable nozzle ring 720 having a seriesof fixed guide vanes 730 attached thereto. Rotation of the ring 720allows for changing of the position of the vanes 730 and thus changingof the angle of attack of the total vane structure. The un-alignedposition of the vanes 730 is shown by dashed lines 735. The embodimentof FIG. 8 provides for an adjustment of the operating point whilereducing the number of moving parts. While the system of FIG. 8 has twonozzle rings, the present disclosure contemplates the use of more thantwo rings which can be various combinations of moveable and non-movablerings for adjustment of the position of each of the vanes 710, 730 withrespect to each other.

FIGS. 9 and 10 show a variable geometry compressor system that allowsfor adjustment of the vane effective chord lengths. The system has avane comprising first, second and third portions 800, 810, 820. Portions800, 810 and 820 are connected to an actuation device, such as anadjustment ring 850, that allow for movement of the vane portions 800,810, 820 along path 830. The extended vane structure is shown in FIG.10. The embodiment of FIGS. 9 and 10 provides for an adjustment of thevane effective chord length in a synchronized manner for flow control tothe compressor wheel. While the system of FIGS. 9 and 10 has threeportions 800, 810, and 820 that are movable with respect to each other,the present disclosure contemplates the use of two or more movable vaneportions.

In the embodiment of FIGS. 11 a and 11 b, efficiency of flow control isenhanced by reducing the gap loss resulting at the forward end of thevane, adjacent to the leading edge of the vane. Vane 900 is adjustablypositioned with respect to adjustment ring 240 through use of pin 265. Abiasing mechanism, such as spring 910, is utilized to bias theadjustment ring towards the vane 900 to reduce or eliminate any gap 905between the ring and the vane. The particular type of biasing mechanism910, e.g., a spring, and the amount of force applied can be selected soas to ensure movement of the vane while minimizing any gap. The numberand configuration of the biasing mechanisms can be chosen to efficientlyreduce or eliminate any gap 905 while still allowing for movement of thevanes 900, such as, for example, a plurality of equidistantly spacedsprings 910 to spread the biasing force with respect to the adjustmentring 240. The adjustment mechanism can be on either the bearing housingside of the vane, or on the compressor housing side of the vane.

In the embodiment of FIGS. 12 a and 12 b, efficiency of flow control isenhanced by reducing the gap losses in the area adjacent to the leadingedge of the vane. Vane 1000 is adjustably positioned with respect to anadjustment ring through use of a pin 265 or the like. A biasingmechanism, such as spring 1010, is utilized to bias the vane toward theadjustment ring and/or compressor housing to reduce or eliminate any gaptherebetween. The particular type of biasing mechanism 1010 and theamount of force applied can be selected so as to ensure movement of thevane while minimizing any gap. The biasing spring 1010 can be one ormore springs positioned within separate housings or portions 1015, 1020of the vane to expand the width of the vane as desired. The biasingmechanism 1010 can also be a compressible or expandable foam or othermaterial applied between the separate housings or portions 1015, 1020.

In the embodiment of FIG. 13, efficiency of flow control is enhanced byreducing the gap loss in the area adjacent to the leading edge of thevanes. Vane 1100 is adjustably positioned with respect to an adjustmentring 240 through use of a pin 265 or the like. A movable ring segment1150 is utilized to reduce or eliminate any gap between the vane and theadjustment ring. The ring segment 1150 is moveably connected to theadjustment ring 240 by bearings 1160 and the like, and can be axiallymoved by various sources including a pneumatic or hydraulic source incommunication with the segment through supply channel 1175. Movement ofthe segment 1150 against or in proximity to the vane 1100 can alsoreduce any gap between the vane and the compressor housing 210.Variations of the pressure supplied through channel 1175 can dynamicallyadjust the vane gaps as needed. The present disclosure also contemplatesmovement of the segment 1150 by other means such as electricalcontrollers, springs or mechanical actuators.

FIG. 14 shows a variable geometry compressor system having a flexiblevane 1200 that is connected to the turbocharger by a rotatable pin 265or the like. The pin 265 is rigidly connected to the vane 1200 and canbe connected to the compressor housing and/or adjustment ring. Pins or afork 1220 abuts against the vane 1200. A rotational force 1210 appliedto pin 265 causes flexing of the vane into the shape shown by dashedline 1250. It should be understood that features of the variousexemplary embodiments can be interchangeable with one another. Theforegoing description is provided in the context of exemplaryembodiments of vanes and vane assemblies for a turbocharger. Thus, itwill of course be understood that the invention is not limited to thespecific details described herein, which are given by way of exampleonly, and that various modifications and alterations are possible withinthe scope of the invention as defined in the following claims.

1. A turbocharger including means for minimizing axial vane gap,comprising: a compressor housing (210); a compressor rotor (230)rotatably mounted in the compressor housing (210); a volute (250) forreceiving a compressible fluid from compressor rotor (230); and a vanering assembly comprising a plurality of vanes (260), the plurality ofvanes (260) being mounted for rotation to control flow of thecompressible fluid in an annular vane space radially between compressorwheel and volute and axially between first and second walls, and meansfor application of axial force between said vanes and at least one ofsaid walls.
 2. A turbocharger as in claim 1, wherein said axial force isa spring force, a hydraulic force, a pneumatic force, or an electricalforce.
 3. The turbocharger of claim 2, wherein said plurality of vanes(260) are mounted on an adjustment ring forming at least a part of, andwherein said means for application of axial force comprises a biasingmechanism (910) that biases the adjustment ring (240), and vanes mountedthereon, towards the wall opposite the adjusting ring.
 4. Theturbocharger of claim 2, wherein said means for application of axialforce comprises a biasing mechanism (1010) that biases each of theplurality of vanes (260) towards the adjustment ring (240) or towardsthe wall opposite the adjusting ring.
 5. The turbocharger of claim 2,wherein said means for application of axial force comprises a biasingmechanism (1010) that biases each of the walls towards each other. 6.The turbocharger of claim 1, wherein said means for application of axialforce comprises is at least one coil spring.
 7. The turbocharger ofclaim 1, wherein each of the plurality of vanes (260) are connected tothe turbocharger by a rotatable pin (265), wherein either the vanes(260) or the adjustment ring (240) has an adjustment pin (380, 480)rigidly connected thereto, wherein the other of the vanes (260) or theadjustment ring (240) has a groove (385, 485), wherein the adjustmentpin (380, 480) is partially inserted into the groove (385, 485), andwherein rotation of the adjustment ring (240) causes rotation of thevanes (260).
 8. The turbocharger of claim 6, wherein each of theplurality of vanes has first and second portions (1015, 1020) that aremoveable axially with respect to each other, and wherein the biasingmechanism (1010) axially biases each of the vane portions.
 9. Aturbocharger comprising: a housing (210); a rotor (230) rotatablymounted in the housing (210); a supply channel (250) for supplying afluid to the rotor (230); and a vane ring assembly having first andsecond nozzle rings (700, 720), the first nozzle ring (700) being fixedwith respect to the turbocharger and having a plurality of first vanes(710), the second nozzle ring (720) being rotatable with respect to theturbocharger and having a plurality of second vanes (730), each of theplurality of first and second vanes (710, 730) being distributed in anannular vane space, each of the plurality of first and second vanes(710, 730) being non-rotatable with respect to the first and secondnozzle rings (700, 720), wherein the second nozzle ring (720) isrotatable from a first position to a second position, wherein in thefirst position the plurality of first vanes (710) are aligned with theplurality of second vanes (720), and wherein in the second position theplurality of first vanes (710) are non-aligned with the plurality ofsecond vanes (720).
 10. A turbocharger as in claim 9, wherein each ofthe plurality of first and second vanes (710, 730) has first and secondportions (1015, 1020) that are moveable with respect to each other, andwherein the biasing mechanism (1010) expands each of the plurality offirst and second vanes (710, 730)